(1) Field of the Invention
The present invention relates to a curable composition which comprises a reactive silicon group-containing polyoxyalkylene polymer, a polyolefin polymer, and a tackifying resin. The invention also relates to an adhesive for waterproof sheets and an industrial adhesive wherein the curable composition is used. The invention relates in particular to a curable composition having an excellent adhesiveness to an adhesion-resistant substrate such as Thermoplastic Polyolefin (hereinafter referred to as TPO) and the use thereof.
(2) Description of the Related Art
It is known that organic polymers each having reactive silicon group(s) in the molecule turn to a rubbery cured product by a matter that the reactive silicon group hydrolyzed by moisture forms a siloxane bond.
Out of such organic polymers having reactive silicon group(s), polymers wherein the main chain thereof is a polyoxyalkylene have already been produced industrially. The polymers are widely used for sealing compounds, adhesives, injections or impregnates, pate materials, paints, and other articles.
These articles are required to have adhesiveness to various materials; thus, in order to give adhesiveness thereto, an adhesion-imparting agent such as a silane coupling agent or a titanium coupling agent is added thereto, thereby improving the adhesiveness (for example, Japanese Laid-Open Patent Application No. 57-182350 and Japanese Laid-Open Patent Application No. 59-024771). Furthermore, an epoxy resin is added thereto, thereby improving the adhesiveness (for example, Japanese Laid-Open Patent Application No. 61-268720), or an acrylic resin compatible therewith is added thereto, thereby improving the adhesiveness (for example, Japanese Laid-Open Patent Application No. 63-112642).
In recent years, investigations have been made for improving the adhesiveness to an adhesion-resistant substrate, such as EPDM (ethylene-propylene-diene based rubber), by the addition of a thermoplastic elastomer to a reactive silicon group-containing organic polymers (for example, Japanese Laid-Open Patent Application No. 2004-323843).
However, a material has not yet been obtained which has a sufficient adhesiveness to a thermoplastic polyolefin (TPO) substrate, which is one adhesion-resistant substrate used in fields of waterproof sheets for roofs, automobiles, and others.